1. Field of the Invention
This invention is the stabilization of vinyl pyridine latex emulsions by the addition of a resorcinolformaldehyde novolak to prevent coagulation caused by mechanical shear.
2. Description of the Prior Art
Various soaps such as alkali metal soaps have historically been used to stabilize vinyl pyridine latex against coagulation caused by mechanical shear. Vinyl pyridine latex has been used extensively in tire cord dips. Prior to use, the vinyl pyridine latex is mixed with a resin forming agent such as resorcinol or a resorcinolformaldehyde novolak, and formaldehyde or a resorcinolformaldehyde resole.
While the soaps used have been very effective in stabilizing the latex against coagulation caused by shear, there have been drawbacks caused by the use of soap stabilizers. For instance, the alkali metal ions of the soap have caused weakening of polyester cord used as a reinforcement in tires. There is also the possibility that during the use of a tire, the soap, which at one time was used as a stabilizer, may migrate to an interface within tire. Collection of soap at an interface could possibly cause separation of the rubber components at that interface. The soaps used also have caused the vinyl pyridine latex cord dips to foam during use. This foaming causes nonuniformity both in the amount of dip applied to a cord, and in the integrity of the coating of the dip on the surface of the cord. Another drawback on the use of soap as stabilizers in vinyl pyridine latex has been the bacterial attack on these latexes unless bactericide is added.